A laser of this type is known from the article "Stimulated Raman Scattering at kHz pulse repetition rates" by E. O. Amman et al, Applied Physics Letters, Vol. 27, No. 12, December 1975, pages 662 to 664.
A Raman medium is positioned between two planar mirrors which form the Stokes resonator. One of these mirrors also acts as a resonator mirror of the pump laser which comprises an arc lamp pumped solid-state laser, an active Q-switch and a further planar mirror. The above article discloses that the solid-state laser typically operates in a low-order transverse mode. Nothing is said about the modes of the Stokes resonator.
As a rule, Raman lasers are configured in such a way that they have a focus in the Raman cell, since the essential nonlinear processes are dependent to a disproportionately high degree on the power density of the pumping light. Thus, this procedure results in lasers with high output powers and high efficiency.
Known Raman lasers are configured as multimode lasers. Multimode lasers display a much more pronounced beam divergence than single-mode lasers. The divergence of a single-mode laser is of the order of magnitude of lambda/D, the ratio of the wavelength to the diameter of the beam at the waist of the Gaussian beam. Compared to the divergence of the single-mode laser, the divergence of a multimode laser beam can be several times higher. In conventional Raman laser systems, the Stokes beam divergence typically is 10.times. larger than the divergence of a diffraction-limited beam. A further serious drawback of multimode lasers is the non-Gaussian beam profile inside the laser resonator. The mixture of many transverse modes in the resonator results in localized hot spots on the laser optics and therefore contributes to laser-induced destruction of the optical system.
An example of such a known intracavity Raman laser is described in U.S. Pat. No. 4,868,833.